Syrian activists say government troops and forces fighting against President Bashar al-Assad's regime have clashed near the border with Jordan.

The fighting near the Al-Nasib border crossing reportedly lasted for several hours on September 22.

The London-based Observatory for Human Rights said casualties were reported on both sides.

Meanwhile, Iraq said on September 22 it had barred a North Korean plane from using its air space on suspicion it was carrying weapons for Syria.

Earlier this week, U.S. officials accused Iraq of allowing Iran to fly arms to Syria using the Iraqi airspace, a charge denied by Baghdad.

The White House said on September 21 that U.S. Vice President Joe Biden discussed in a telephone call with Iraqi Prime Minister Nuri al-Maliki the need to prevent Iraqi territory and airspace from being used to ship weapons to Syria.

Also on September 22, the leaders of the rebel Free Syrian Army said they had moved their command center from Turkey to Syria.

Free Syrian Army (FSA) chief Riad al-Asaad said in a video sent to media that "the Free Syrian Army command has moved into liberated areas of Syria following arrangements made with battalions and brigades to secure these zones."

There was no indication of where in Syria the command center is located.

The FSA has been the most prominent of the rebel groups trying to remove Assad from power.

But its commanders have come under criticism in the past for leading from Turkey, and its authority over numerous locally-based networks of fighters is limited.